1. Field of the Invention
This invention relates to a hydrostatic line tester and method of testing a fluid filled line for leaks and more particularly to apparatus for testing whether a pipe filled with a volatile liquid, such as gasoline, is leaking.
2. Objects and Description of the Prior Art
The apparatus disclosed in the aforementioned patent application is particularly adapted to testing whether an underground liquid filled storage tank, such as that typically found in a retail gasoline station, is leaking. The apparatus disclosed therein includes a constant level leak detector which applies a substantially constant head to a gasoline filled tank throughout the test.
As recited in the aforementioned prior art application, serious environmental problems are occasioned if an underground fuel tank leaks. Environmental protection agencies set forth the standard for maximum leakage allowable in fuel tanks.
Although the tanks can be a major source of underground contamination, the pipes leading to the tanks for drawing out the liquid gasoline to the above ground dispensers must also be substantially leak free. Obviously, if there is a leak in a pipe which transfers fuel to or from the tank, this could pose a substantial environmental hazard to water supply systems and the like.
Accordingly, it is an object of the present invention to provide a new and novel line tester for testing whether or not fuel filled lines leading to such fuel tanks are leaking.
Another object of the present invention is to provide new and novel hydrostatic line testing apparatus and method of leak testing a fluid filled line.
As recited in the aforementioned patent application, some prior art leak detectors have utilized a pressurized gas for maintaining force on the liquid in the vessel being tested. The use of such gas is potentially hazardous, particularly if the liquid in the vessel being tested is volatile, such as gasoline. It is another object of the present invention to provide a new and novel line tester which is safer than other prior art line testers which utilize a gas under pressure for maintaining pressure on liquid in the liquid filled line being tested.
A further object of the present invention to provide hydrostatic line testing apparatus which utilizes liquid instead of a gas for maintaining pressure on the liquid in a line being leak tested.
It is a still further object of the present invention to provide hydrostatic line testing apparatus which utilizes a liquid, having a different density than the liquid in the line being tested, under pressure for maintaining pressure on the liquid in the line being leak tested.
Yet another object of the present invention is to provide line testing apparatus of the type described which utilizes a pressurizing liquid, having a density heavier than the density of the liquid in the line being tested, for maintaining pressure on the liquid in the line.
Various leak detectors such as that disclosed in U.S. Pat. No. 4,907,464 issued to Lewis J. Janotta on Feb. 28, 1989, include various gages, measuring devices and data collector and processors for providing a readout of volumetric changes. Such systems are relatively complicated and expensive. Accordingly, it is an object of the present invention to provide new and novel leak testing apparatus which is easier and less expensive to build than the competing prior art test apparatus.
Still another object of the present invention to provide new and novel line test apparatus of the type described which includes a graduated cylinder for providing a visual indication of volumetric changes of the liquid in the line being tested.
It is another object of the present invention to provide new and novel method and apparatus for testing whether a fuel supply line which leads to an underground fuel storage tank is leaking including apparatus for isolating the fuel filled supply lines from the fuel tank.
Other objects and advantages of the present invention will become apparent to those of ordinary skill in the art as the description thereof proceeds.